In the 3GPP System Architecture Evolution (SAE) network, the access network accesses the Packet Data Network (PDN) Gateway (GW) over an S2a/b/c interface to get access to the PDN, where the S2c interface is applicable to any access network such as a non-3GPP network and a 3GPP network. Mobility management is performed by using a DS-MIPv6 protocol, and the PDN GW serves as a Mobile IP (MIP) Home Agent (HA). The Policy and Charging Rules Function (PCRF) makes the decision of policy and charging rules for each service data. The PDN GW in the core network is a Policy and Charging Enforcement Function (PCEF), and is a network element that performs the policy and charging control rules of the data stream. The policy control includes Quality of Service (QoS) control.
The prior art provides a process for a UE to access the SAE network from a non-3GPP access network, and a process of obtaining IP-CAN session policy control information in a Policy and Charging Control (PCC) protocol.
In the process of developing the present invention, the inventor finds at least the following defects in the prior art:
The process of obtaining IP-CAN session policy control information is: The UE sends an MIP Binding Update request to the PDN GW to request setup of an IP-CAN session. The request sending triggers information exchange between the PDN GW and the PCRF to obtain the policy control information. The information exchange process does not involve the access gateway, and therefore the access gateway does not obtain the IP-CAN session policy control information. The PDN GW serves as a PCEF on the IP-CAN session path, and the access gateway serves as another PCEF on the IP-CAN session path. The access gateway is unable to perform policy and charging control on the service data between the UE and the PDN for lack of the IP-CAN session policy control information.